JP5202071B2 - Charged particle microscope apparatus and image processing method using the same - Google Patents

Description

  The present invention relates to a charged particle microscope that irradiates a sample with charged particles and acquires an image, and an image processing method using the charged particle microscope, and in particular, an image quality improving method for performing image quality improvement processing by image processing on an acquired image and the image processing method Relates to the device.

  In order to clearly observe the fine structure of an object to be observed, charged particle microscopes having a very high resolution compared to optical microscopes are widely used. A charged particle microscope irradiates a target sample with a charged particle beam and detects particles emitted from the target sample or transmitted through the target sample (same or different types of charged particles or electromagnetic waves that are irradiated). , Get an enlarged image of the target sample.

  In particular, in the semiconductor manufacturing process, scanning electron microscopes (SEM), scanning ion microscopes (SIM), scanning transmission electron microscopes (SEM) are used for inspection of semiconductor wafers and pattern measurement. A charged particle microscope such as a scanning transmission electron microscope is used. In these applications, the captured images are used to observe semiconductor patterns and defects, detect defects and analyze the causes of the defects, and measure the dimensions of the patterns.

  The function of providing high-quality images in a charged particle microscope is one of the most important functions. Although it is possible to achieve high resolution and high S / N of captured images to some extent by improving hardware such as charged particle optics and detection systems, there are limitations. Regarding resolution, resolution degradation always occurs due to the influence of diffractive aberration caused by charged wave characteristics, chromatic aberration caused by charged particle lens characteristics, and spherical aberration. In addition, with regard to S / N, it is generally possible to achieve a higher S / N by increasing the amount of charged particle beam to be irradiated, but on the other hand, damage to the sample and longer imaging time Due to problems, the amount of charged particle beam that can be irradiated is actually limited, and sufficient S / N may not be ensured.

  As a measure different from hardware improvement, there is a method for improving resolution and S / N by applying image quality improvement processing to captured images by image processing. Patent Documents 1 and 2 propose edge enhancement processing, image restoration processing, noise removal processing, and the like as processing for improving resolution and S / N. In addition, as a method for improving image quality other than the above, a method has been proposed in which contrast correction processing is performed on a captured image to appropriately adjust brightness and contrast to improve the output image quality (for example, non-image quality improvement). Patent Document 1).

  Japanese Patent Application Laid-Open No. 2004-228561 describes that two images are aligned using a matching process.

JP 63-211142 A Japanese Patent Laid-Open No. 3-44613 JP 2002-328015 A Y.I.Gold and A.Goldenshtein: Proc.SPIE, 3332, pp.620-624 (1998)

  In the methods proposed in Patent Documents 1 and 2 and Non-Patent Document 1, image quality improvement processing is performed using only captured images, or captured images and imaging conditions (accelerating voltage of charged particle beam, probe current, etc.) ) Has been used to improve the image quality. However, in the above method, processing using design data and processing using design data and sample characteristic information have not been performed. Here, the design data refers to data indicating the shape information of the semiconductor pattern to be manufactured, and in many cases, the shape of the semiconductor pattern is described by information on the outline.

For this reason, the conventional processing may not provide sufficient image quality improvement performance as listed below.
Sample characteristics information in each area on the image cannot be obtained only with the captured image and imaging conditions, and spatially separated areas on the image have similar sample characteristics (material characteristics, electrical characteristics, layer characteristics, etc.). It cannot be determined whether or not it has. For this reason, it is impossible to perform appropriate image quality improvement processing on each region according to the sample characteristics, reveal differences in sample characteristics, or emphasize only samples having specific characteristics.
In the conventional method, in order to enhance the contrast between different areas and to perform the process of optimizing the processing parameters for each area, it is necessary to perform image area division. However, there is a problem that the region division requires a long processing time, and it is difficult to achieve both the accuracy of region division and the processing time.
The area on the sample that the user particularly wants to observe is often an area where the difference from the design data is large. Image quality improvement processing that automatically emphasizes such areas is difficult with conventional methods.

  An object of the present invention is to provide a charged particle microscope apparatus capable of acquiring an image with improved image quality by solving the above-described problems of the prior art and an image processing method using the same.

  In order to achieve the above object, in the present invention, when processing an image acquired by a charged particle microscope that performs inspection, observation, pattern measurement, etc. of a semiconductor wafer, the above-described image quality improvement method is employed to Solved the problem.

  That is, in the present invention, a charged particle beam irradiation unit that scans the surface of a sample on which a pattern is formed by applying a focused charged particle beam to a charged particle microscope apparatus, and the charged particle beam is emitted by the charged particle irradiation unit. A charged particle image acquisition means comprising a secondary charged particle image acquisition unit for detecting secondary charged particles generated from the sample by irradiation and scanning to generate a secondary charged particle image of the sample surface; Image processing means for processing the secondary charged particle image of the sample surface generated by the charged particle image acquisition means, and output means for outputting the result processed by the image processing means, the image processing means, An image quality improvement unit for improving the image quality of the secondary charged particle image on the sample surface generated by the charged particle image acquisition means using the design data of the pattern formed on the sample, and an image with the image quality improved by the image quality improvement unit Processes and defect detection of the sample, and having an image processing unit that performs processing of one of the dimension measurement for obtaining the defect image, or the pattern.

  Further, in the present invention, a secondary charged particle image generated on the sample surface is detected by irradiating and scanning the surface of the sample on which the pattern is formed with a focused charged particle beam to detect secondary charged particles generated from the sample. In the image processing method using the charged particle microscope apparatus that processes the generated secondary charged particle image of the sample surface, the second surface of the generated sample surface is generated using design data of the pattern formed on the sample. The image quality of the next charged particle image is improved, and the image with the improved image quality is processed to perform any of the defect detection of the sample, acquisition of the defect image, or dimension measurement of the pattern.

According to the present invention, the charged particle microscope image is subjected to image quality improvement processing using design data and sample characteristic information, thereby achieving high accuracy in image quality improvement processing and region segmentation processing that reflect differences in sample characteristics. And speeding up, highlighting of areas where the difference between the design data and the captured image is large, and so on, detecting defects in the sample by image processing, acquiring defect images, or measuring the dimensions of the pattern with high accuracy I was able to do it.

  The present invention uses the information held in the design data to capture images obtained with a charged particle microscope in order to observe semiconductor patterns and defects, detect defects and analyze the cause of the defects, and measure the dimensions of the patterns. This is a high-performance image quality improvement process.

  DESCRIPTION OF EMBODIMENTS Hereinafter, a case where an embodiment according to the present invention is applied to a defect observation apparatus (review SEM) or a pattern dimension measurement apparatus (CD-SEM) using a scanning electron microscope (SEM) will be described. It explains using.

  FIG. 1 is a diagram illustrating an example of a sequence for performing image quality improvement processing by capturing an image of a sample with a system using an SEM (hereinafter referred to as an SEM system). First, a sample with a pattern formed on the surface is imaged in step 101 using an SEM, and a captured image (SEM image) 111 is acquired. In step 102, design data (CAD data) 112 of the pattern formed on the surface of the sample is read, and design data 112 corresponding to the captured image 111 is acquired. Since a positional deviation generally occurs between the captured image 111 and the design data 112, the design data 112 acquires at least data with a field of view wider than the field of view of the captured image 111, and an area corresponding to the captured image 111 is present. To be included. Next, in step 103, the design data 112 is aligned using the captured image 111, and the design data 113 after alignment is obtained.

  The alignment will be described with reference to FIG. In FIG. 6, when positioning the captured image 111 and the design data 112, the design data is necessary in the x and y directions so that the captured image and the design data are aligned as in 611. shift. There are various methods for specific alignment processing, and for example, matching processing as described in Patent Document 3 may be used. Next, using the design data 113 after alignment, the image quality improvement processing of the captured image is performed in step 104 to generate an image quality improved image 114.

  Further, by performing image processing in step 105 using the image whose image quality has been improved in step 104, semiconductor pattern and defect observation, defect detection and generation factor analysis, pattern dimension measurement, and the like may be performed.

  According to this embodiment, it is possible to perform image quality improvement processing using information such as pattern area information, edge position, and edge direction, which is information included in design data. For example, processing parameters can be set according to pattern area information. It can be changed appropriately. In addition, the edge of the pattern is blunted by changing the degree of noise removal and edge enhancement in the pattern edge or its neighboring area and the area not including the pattern edge, or by performing smoothing processing along the pattern edge direction. It is also possible to perform processing such as high S / N without any problems at high speed. A dotted arrow in the drawing indicates that data or an image at the base of the arrow is used in an auxiliary manner in the processing at the tip of the arrow.

  FIG. 2 shows a basic configuration of an SEM system according to an embodiment of the present invention. The SEM system according to the present invention includes an imaging device 201, an input / output unit 221, a control unit 222, an image generation unit 223, an image processing unit 224, a storage unit 225, an image quality improvement unit 226, and the like.

  In the imaging device 201, an electron beam 203 is generated from the electron gun 202, and the generated electron beam 203 is focused on the surface of the sample 200 by passing through the condenser lens 204 and the objective lens 205, and the electron beam 203 is focused by the deflection electrode 206. By deflecting the orbit, the surface of the sample 206 is scanned and irradiated with the electron beam 203.

  Next, by scanning and irradiating the surface of the sample 206 with the electron beam 203, secondary electrons or reflected electrons generated from the sample 200 are detected by the detector 208, and detected by the A / D converter 209. The analog signal thus obtained is converted into a digital signal and input to the image generation unit 223. The image generation unit 223 generates an image by processing the digital signal using a signal for controlling the deflection electrode 206 or a signal for controlling the stage 207 by the control unit 222, and acquires a captured image. The acquired captured image is stored in the storage unit 225. A plurality of detectors 208 may be provided, and these detectors may be detectors that detect different types of particles (secondary electrons and reflected electrons). Further, a configuration in which a plurality of captured images are acquired by one imaging may be employed.

  The sample 200 is placed on the stage 207, and the image at an arbitrary position of the sample can be acquired by moving the stage 207 under the control of the control unit 222. The imaging device 201, the input / output unit 221, the control unit 222, the image generation unit 223, the image processing unit 224, the storage unit 225, and the image quality improvement unit 226 are connected to each other via a signal line 220.

  The input / output unit 221 includes a display 2210, and performs input of an image capturing position and imaging conditions, output of a captured image and an image quality improved image, and the like via a GUI (Graphic User Interface) displayed on the display 2210.

  The control unit 222 controls the image pickup apparatus by adjusting the voltage applied to the electron gun 202 and the like, the focal positions of the condenser lens 204 and the objective lens 205, and the deflection electrode 206 (a pair of X direction control electrodes and a pair of Y The voltage applied to the direction deflection control electrode), the movement of the stage 207, the operation timing of the A / D converter 209, and the like are controlled. The control unit 222 also controls the input / output unit 221, the image generation unit 223, the image processing unit 224, the storage unit 225, and the image quality improvement unit 226.

  The image processing unit 224 performs processing other than the image quality improvement processing, for example, processing related to automatic focusing necessary for focusing the electron beam 203 on the surface of the sample 200, and an image whose image quality has been improved by the image quality improvement unit 226. Using this, processes such as semiconductor pattern and defect observation, defect detection and generation factor analysis, and pattern dimension measurement are performed. When observing a semiconductor pattern or defect, an image including the semiconductor pattern or defect whose image quality has been improved by the image quality improvement unit 226 is used to compare the image with the semiconductor pattern or defect as in the conventional technique. To extract. Since the extracted image is an image with improved image quality, the image feature amount of the semiconductor pattern or the defect can be extracted with higher reliability and accuracy. As a result, it becomes possible to accurately evaluate the shape of finer semiconductor patterns, classify defect images, and investigate the cause of defects. Further, when pattern dimension measurement is performed, measurement accuracy can be improved and measurement reproducibility can be improved by using an image with improved image quality.

  The storage unit 225 stores captured images, design data, sample characteristic information, image quality improved images, processing parameters for improving image quality, and the like. As the design data, necessary data may be read out from data stored in other storage means (not shown) via a communication line, and input to the storage unit 224 for storage.

  The image quality improvement unit 226 performs a series of processes for generating an image quality improved image from the captured image shown in FIG. As shown in FIG. 2, the image quality improvement unit 226 includes a design data reading unit 231 that performs design data reading 102, an alignment unit 232 that performs alignment 103, and an image quality improvement processing unit 233 that performs image quality improvement processing 104. ing. The image quality improvement unit 226 may further include a shape information correction unit (not shown) that performs shape information correction 301 described later, a sample characteristic reading unit (not illustrated) that performs sample characteristic reading 401 described later, and the like. .

  FIG. 3A is a diagram illustrating an example of a sequence for performing image quality improvement processing using design data in which shape information is corrected. The same processes or data as in FIG. 1 are denoted by the same numbers as in FIG. The contents of each process of the image capturing 101, the design data reading 102, and the alignment 103 are the same as those described with reference to FIG.

  In this embodiment, the design data 311 after the shape information correction is obtained by performing the shape information correction 301 on the design data 113 after the alignment obtained by the alignment 103. The shape information correction 301 can be performed by lithography simulation (simulating a process of forming a pattern on a wafer by etching using a resist pattern as a mask, thereby calculating a pattern shape formed on the wafer). it can. Or you may correct using the information of a captured image.

  Next, an image quality improvement image 312 is generated by performing image quality improvement processing 302 on the captured image 111 using the design data 311 after the shape information correction. By using the design data 311 after the shape information correction, more accurate information such as the edge position and edge direction of the pattern can be acquired, so that higher-performance image quality improvement processing can be performed.

  FIG. 3B shows the configuration of the image quality improvement unit 226 'in this embodiment. Portions having the same functions as those of the image quality improvement unit 226 described with reference to FIG. In this embodiment, the image quality improvement unit 226 ′ includes a design data reading unit 231 that performs design data reading 102, an alignment unit 232 that performs alignment 103, a shape information correction unit 234 that performs shape information correction 301, and an image quality improvement process 302. An image quality improvement processing unit 233 ′ is provided.

  The content of the image processing 105 processed by the image processing unit 224 using the image quality improved image 312 that has been subjected to the image quality improving processing 302 is the same as the content of the processing described with reference to FIG.

  FIG. 4A is a diagram showing an example of a sequence for performing image quality improvement processing using design data and sample characteristic information. In this embodiment, information on sample characteristics (material characteristics, electrical characteristics, layer characteristics, etc.) in each region as shown in the table 411 is stored in the storage unit 225 in advance. With respect to the design data 113 after alignment obtained by the alignment 103, the sample characteristics 412 corresponding to each area in the design data 112 are read from the table 411 by reading the sample characteristics 401.

  Next, by the image quality improvement process 402, the image quality improvement process 402 is performed on the captured image 111 using both the design data 113 after alignment and the corresponding sample characteristic 412 to obtain an image quality improvement image 413. This process enables image quality improvement processing that reflects sample characteristics. For example, highlighting only areas made of a specific material, adding a contrast difference in a low-contrast location in the lower layer, or charging positively. It is possible to freely perform processing such as brightly displaying easy-to-use areas. Of these types of processing, the type of processing that is most appropriate varies depending on the purpose and situation. Therefore, the user should be able to specify information related to the characteristics to be highlighted and input from the user. The processing may be performed according to

  4B shows the configuration of the image quality improvement unit 226 ″ in the present embodiment. Parts having the same functions as those of the image quality improvement unit 226 described in FIG. The improvement unit 226 ″ includes a design data reading unit 231 that performs design data reading 102, a positioning unit 232 that performs positioning 103, and a sample property reading unit that reads information on the sample properties 412 from the table 411 stored in the storage unit 225. 235, and an image quality improvement processing unit 233 "that performs image quality improvement processing 402.

  The content of the image processing 105 processed by the image processing unit 224 using the image quality improved image 413 that has been subjected to the image quality improving processing 402 is the same as the content of the processing described with reference to FIG.

  FIG. 5A is a diagram showing an example of a sequence for performing segmentation based on design data and performing image quality improvement processing using the result. Here, segmentation represents the process of subdividing an image into several regions. The subdivision of the image is performed by dividing the captured image 111 for each pattern region using the design data 113 after alignment, or by grouping for each similar pattern.

  The processing flow shown in FIG. 5 (a) will be described. First, in the step of image capturing 101, a captured image 111 is acquired by capturing an image of a sample having a pattern formed on the surface using the image capturing apparatus 201. In step 102, the design data 112 of the pattern formed on the surface of the sample is read, and the design data 112 corresponding to the captured image 111 is acquired. Next, in the step of alignment 103, the positional deviation between the captured image 111 and the design data 112 is corrected. The design data 113 whose positional deviation is corrected in the step of alignment 103 is subjected to segmentation 501 and the captured image. 111 segmentation is performed and a segmentation result 511 is obtained. Next, using the segmentation result 511, image quality improvement processing 502 is performed for each region divided by segmentation, and an image quality improved image 512 is generated.

In the image quality improvement processing 502, the design data 113 after alignment may be used. Further, the segmentation 501 may be performed on an image in the middle of the image quality improvement processing 502 instead of being performed on the captured image 111. According to the present embodiment, image quality improvement processing using an image divided into regions can be performed, so that processing such as performing different image quality improvement processing depending on the region or changing processing parameters such as the degree of contrast enhancement can be easily performed. Yes.
FIG. 5B shows the configuration of the image quality improvement unit 226 ′ ″ in this embodiment. Portions having the same functions as those of the image quality improvement unit 226 described with reference to FIG. The image quality improvement unit 226 ′ ″ in this embodiment includes a design data reading unit 231 that performs design data reading 102, an alignment unit 232 that performs alignment 103, a segmentation unit 236 that performs segmentation of the captured image 111, and an image quality improvement process. An image quality improvement processing unit 233 ′ ″ that performs 502 is provided.

  The content of the image processing 105 processed by the image processing unit 224 using the image quality improved image 512 that has been subjected to the image quality improving processing 502 is the same as the content of the processing described with reference to FIG.

  FIG. 7A is a diagram showing an embodiment of a sequence for performing image quality improvement processing using data stored in a database. The processing flow shown in FIG. 7 will be described. First, in the step of image capturing 101, a captured image 111 is acquired by capturing an image of a sample having a pattern formed on the surface using the image capturing apparatus 201. In step 102, the design data 112 of the pattern formed on the surface of the sample is read, and the design data 112 corresponding to the captured image 111 is acquired. Next, in the alignment 103 step, a positional deviation between the captured image 111 and the design data 112 is corrected, and a database reference 701 that refers to the database 711 using the design data 113 after the alignment in which the positional deviation is corrected. I do. The database 711 stores design data and corresponding image information.

  The image information is a captured image, an image quality improved image, information obtained from those images, or information related to those images. The image information may include, for example, edge information obtained by performing edge extraction processing on a captured image, processing parameters for image quality improvement processing, and the like. In the step of database reference 701, design data similar to the design data 113 after alignment is searched from the database 711, and corresponding image information 712 is acquired. Next, in the step of image quality improvement processing 702, image quality improvement processing is performed on the captured image 111 using the design data 113 and image information 712 after alignment, and an image quality improved image 713 is generated.

  FIG. 7B shows the configuration of the image quality improvement unit 226 ″ ″ in this embodiment. Portions having the same functions as those of the image quality improvement unit 226 described with reference to FIG. The image quality improvement unit 226 ″ ″ in this embodiment includes a design data reading unit 231 that performs design data reading 102, a positioning unit 232 that performs positioning 103, and a database reference unit 237 that refers to the database 711 using the design data 113. And an image quality improvement processing unit 233 ″ ″ that performs image quality improvement processing 702.

  The content of the image processing 105 processed by the image processing unit 224 using the image quality improvement image 713 that has been subjected to the image quality improvement processing 702 is the same as the content of the processing described with reference to FIG.

  If necessary, the database storage 703 stores the design data 113 after alignment, the captured image 111, the image quality improved image 713, and the like in the database 711. 7 indicates a flow of data stored in the database 711 in the processing flow of the database storage 703. According to the present embodiment, it is possible to perform image quality improvement processing using information related to images acquired in the past in similar circuit patterns. Therefore, it is possible to achieve higher S / N by performing averaging with images acquired in the past, or to use the same processing parameters as other image quality improved images with similar circuit patterns. It is possible to perform processing such as suppressing the difference between the two.

  FIG. 8 is a diagram showing an embodiment of a GUI screen 800 for setting processing parameters in image quality improvement processing using design data. This GUI screen is displayed on the screen of the display 2210 connected to the input / output unit 221 in the apparatus configuration shown in FIG. In this embodiment, an example is shown in which this GUI screen is configured to include areas for displaying setting items relating to display intensity 801, setting items relating to brightness and contrast 802, and setting items relating to database use 803, respectively.

  In the setting item 801 related to display intensity, for example, there is a setting item related to display intensity 812 in the edge portion 811 or lower layer of the pattern. In the setting item 802 relating to the brightness and contrast, for example, the setting item 821 relating to the brightness of the hole bottom in the region where the hole is formed on the sample, the setting item 822 relating to the contrast in the same region, and the setting item 823 relating to the contrast between different regions. and so on. Further, there may be a setting item 824 for associating an area having specific sample characteristics with a display level. The setting item 803 relating to the use of the database includes, for example, a setting item 806 for specifying whether or not to use the database, a setting item 807 for performing addition averaging with captured images corresponding to similar design data, and the like. is there. Further, there may be a preview screen 804 regarding the image quality improvement result.

  In the preview screen 804, for example, the processing parameters specified in the design data example 812, the captured image example 813, the setting item 801 relating to display intensity, the setting item 802 relating to brightness and contrast, the setting item 803 relating to use of the database, and the like are displayed. An image quality improved image example 814 obtained by performing the image quality improving process using the image quality is displayed. By providing such a GUI screen 800, it is possible to provide an image suitable for the user according to the image quality evaluation criteria of each user.

  FIG. 9 is a diagram illustrating an example showing the necessity of performing the image quality improvement processing 702 using data stored in the database 711 as shown in the embodiment of FIG. The captured image 901 and the captured image 902 are examples of images obtained by capturing the same pattern. In the captured image 902, a foreign object 903 is on the pattern. In this case, if image quality improvement processing is performed on each captured image without using design data information, the contrast and the like may differ greatly between the captured images 901 and 902 due to the influence of the foreign material 903. On the other hand, in consideration of the absence of foreign matter on each design data 112, the contrast of the captured image 901 and the captured image 902 can be made uniform by using the information of the design data 112. Furthermore, stable processing is possible by using the data stored in the database 711. For example, when an image quality improvement process is performed on the captured image 902, if an image such as the captured image 901 can be retrieved by retrieving a captured image having similar design data from the database 711, the captured image 901 can be retrieved. It is possible to perform the image quality improvement processing of the captured image 902 using the processing parameters of the image quality improvement processing.

  FIG. 10 is an example diagram showing the effect of performing edge enhancement processing using design data in the SEM system. When a location corresponding to the design data 1001 is imaged, an image such as a captured image 1002 is obtained. Here, an arrow 1013 represents the scanning direction of the charged particle beam during image capturing. In this embodiment, the charged particle beam is scanned in the horizontal direction. In this case, the vertical edge 1011 orthogonal to the scan direction is clearly displayed in the captured image 1002, but is parallel to the scan direction. Certain lateral edges 1012 may result in low contrast. However, by using the information of the design data 1001, it can be seen that the edge 1012 in the horizontal direction exists, so this edge is displayed with emphasis, and the vertical and horizontal edges are displayed as in the image quality improved image 1003. It is possible to generate an image having the same degree of contrast.

  FIG. 11 is a diagram illustrating an example showing the effect of highlighting a lower layer using design data (CAD data). When a location corresponding to the design data 1101 is imaged, there may be a case where sufficient contrast cannot be obtained in the lower layer 1112 as in the captured image 1102. On the other hand, when it is desired to observe the lower layer, it is desirable to perform image quality improvement processing that emphasizes the lower layer. In addition, for example, there is a case where it is desired to measure the width of a pattern in a region located directly above a lower layer such as a region 1111 among upper layers. In this case, it may be difficult to find the location 1111 if the lower layer is not sufficiently highlighted. Even in such a case, if the lower layer can be highlighted and displayed as in the image quality improved image 1103, the above-described requirement can be satisfied.

  In the above-described embodiment, the case of a defect observation apparatus (review SEM) or a pattern dimension measurement apparatus (CD-SEM) is described as an example of a system using a scanning electron microscope (SEM). However, the present invention is not limited to this, and can be applied to a pattern defect inspection apparatus using a scanning electron microscope (SEM).

  Further, the present invention can be applied to a system using a scanning ion microscope (SIM) or a scanning transmission electron microscope.

It is an example figure of a sequence which picturizes an image and performs image quality improvement processing. 1 is a basic configuration of a charged particle microscope according to an embodiment of the present invention. It is an example of the sequence which performs an image quality improvement process using the design data which corrected the shape information. It is an example figure of the sequence which performs an image quality improvement process using design data and sample characteristic information. It is an example of the sequence which performs segmentation based on design data, and performs an image quality improvement process using the result of this segmentation. It is an Example figure showing alignment of design data using a captured image. It is an Example figure of the sequence which performs an image quality improvement process using the data stored in the database. It is an example figure of the GUI screen for setting the process parameter in the image quality improvement process using design data. It is an Example figure showing the necessity of performing an image quality improvement process using the data stored in the database. It is an Example figure showing the effect of performing an edge emphasis process using design data in a scanning charged particle microscope. It is an Example figure showing the example which highlights a lower layer using design data.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 ... Image pick-up process, 102 ... Design data reading process, 103 ... Position alignment process, 104 ... Image quality improvement process, 111 ... Captured image, 112 ... Design data, 113 ... Design data after position alignment, 114 ... Image quality improvement image, DESCRIPTION OF SYMBOLS 201 ... Imaging device, 202 ... Charged particle gun, 203 ... Charged particle beam, 204 ... Condenser lens, 205 ... Objective lens, 206 ... Sample, 207 ... Stage, 208 ... Detector, 209 ... Image generator, 221 ... Input / output 222, control unit, 223 ... processing unit, 224 ... storage unit, 225 ... image quality improvement unit, 231 ... design data reading unit, 232 ... alignment unit, 233 ... image quality improvement processing unit, 301 ... shape information correction processing, 302 ... Image quality improvement processing, 311 ... Design data after shape information correction, 312 ... Image quality improvement image, 401 ... Sample characteristic reading processing, 402 ... Image Improvement processing, 411 ... table, 412 ... sample characteristics, 413 ... image quality improvement image

Claims (14)

A charged particle beam irradiation unit that irradiates and scans the surface of a sample on which a pattern is formed with a focused charged particle beam, and the charged particle beam generated by the charged particle beam irradiation unit scans the charged particle beam. Charged particle image acquisition means comprising a secondary charged particle image acquisition unit that detects secondary charged particles and generates a secondary charged particle image of the sample surface;
Image quality improvement means for processing secondary charged particle images of the sample surface generated by the charged particle image acquisition means;
A charged particle microscope apparatus comprising output means for outputting a result processed by the image processing means,
The image quality improvement means aligns the position of the design data of the pattern formed on the sample and the secondary charged particle image of the sample surface generated by the charged particle image acquisition means, and then acquires the secondary charged particle image. The sample surface generated by the charged particle image acquisition means using the information of the design data obtained by correcting the pattern information of the design data using the secondary charged particle image acquired by the unit A charged particle microscope apparatus characterized by performing any one of edge enhancement processing, image restoration processing, noise removal processing, and contrast correction processing as an improvement of the secondary charged particle image.   The charged particle image acquisition unit is a scanning electron microscope (SEM), and the image quality improvement unit improves the image quality of an SEM image of a sample acquired by the scanning electron microscope (SEM). Item 3. A charged particle microscope apparatus according to Item 1.   The charged particle microscope apparatus further includes an image processing unit that processes an image whose image quality has been improved by the image quality improving unit to detect a defect of the sample, acquire a defect image, or measure a dimension of the pattern. The charged particle microscope apparatus according to claim 1, further comprising: The image quality improvement means aligns the position of the design data of the pattern formed on the sample and the secondary charged particle image of the sample surface generated by the charged particle image acquisition means, and then uses the design information to The next charged particle image is divided into regions, different processing parameters are set using sample characteristic information included in the design data for each of the regions divided using the design data , and the set different processings are performed. The charged particle microscope apparatus according to claim 1, wherein the image quality of the secondary charged particle image is improved using a parameter . The sample characteristic information included in the design data, the charged particle microscope according to claim 1, wherein either Der Rukoto of material properties or electrical properties of the sample.   The image quality improvement means aligns the position of the design data of the pattern formed on the sample and the secondary charged particle image of the sample surface generated by the charged particle image acquisition means, and then uses the design information to An edge of a pattern included in a next charged particle image is extracted, and the edge enhancement processing is performed so that a contrast of an edge parallel to the scanning direction of the charged particle beam is increased among the extracted edges. Item 3. A charged particle microscope apparatus according to Item 1.   The image quality improvement means aligns the position of the design data of the pattern formed on the sample and the secondary charged particle image of the sample surface generated by the charged particle image acquisition means, and then uses the design information to The edge of the pattern included in the next charged particle image is extracted, and the edge enhancement processing is performed so that the contrast between the extracted edge and the edge orthogonal to the edge parallel to the scanning direction of the charged particle beam is approximately the same. The charged particle microscope apparatus according to claim 1, which is performed. By irradiating and scanning the focused charged particle beam on the surface of the sample on which the pattern is formed, secondary charged particles generated from the sample are detected to generate a secondary charged particle image on the sample surface, An image processing method using a charged particle microscope apparatus that processes a secondary charged particle image of the generated sample surface,
After aligning the position of the design data of the pattern formed on the sample and the secondary charged particle image on the sample surface generated by the charged particle image acquisition means, the second acquired by the secondary charged particle image acquisition unit The pattern shape information of the design data is corrected using a secondary charged particle image, and the image quality of the secondary charged particle image on the generated sample surface is improved using information held in the design data in which the shape information is corrected. An image processing method using a charged particle microscope apparatus characterized by performing any one of enhancement processing, image restoration processing, noise removal processing, and contrast correction processing.   The focused charged particle beam is an electron beam, the secondary charged particle image on the sample surface is an SEM image, and the image quality of the SEM image on the sample surface is improved using the design data. An image processing method using the charged particle microscope apparatus according to claim 8.   In order to improve the image quality, after aligning the position of the pattern design data formed on the sample and the secondary charged particle image on the sample surface, the secondary charged particles using design information or sample characteristic information are used. The image processing method using the charged particle microscope apparatus according to claim 8, wherein the image quality of the image is improved. In order to improve the image quality, after aligning the design data of the pattern formed on the sample and the secondary charged particle image on the sample surface, the secondary charged particle image is divided into regions using design information. Different processing parameters are set using sample characteristic information included in the design data for each of the regions divided using the design data , and the secondary processing is performed using the set different processing parameters. The image processing method using a charged particle microscope apparatus according to claim 8, wherein the image quality of the charged particle image is improved. Sample characteristic information included in the design data, an image processing method using a charged particle microscope according to claim 8, wherein either Der Rukoto of material properties or electrical properties of the sample.   The improvement of the image quality is achieved by aligning the position of the design data of the pattern formed on the sample and the secondary charged particle image on the sample surface, and then using the design information to determine the pattern included in the secondary charged particle image. The charged particle microscope apparatus according to claim 8, wherein an edge is extracted, and the edge enhancement processing is performed so that a contrast of an edge parallel to a scanning direction of the charged particle beam is increased among the extracted edges. The image processing method used.   The improvement of the image quality is achieved by aligning the position of the design data of the pattern formed on the sample and the secondary charged particle image on the sample surface, and then using the design information to determine the pattern included in the secondary charged particle image. 9. The edge enhancement processing is performed by extracting an edge, and performing the edge enhancement processing so that a contrast between an edge parallel to the scanning direction of the charged particle beam and an edge perpendicular to the extracted edge is approximately the same. An image processing method using the described charged particle microscope apparatus.

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